October Journal Round-Up

Welcome to the October journal round-up!

Vascular Mokin et al. tackle the issue of ASPECTS subjectivity in an interesting article in Stroke this month, using Hounsfield unit measurements (as a ratio and subtraction with the unaffected side) to provide a more objective measure and pave the way for automated image interpretation. This would hopefully standardise and speed up management decisions in thrombectomy, but requires validating in more extensive datasets.

Also considering automated assessments, Hanning et al. developed an automated segmentation and analysis of white matter lesion density on CT and showed a reasonable correlation with subsequent MRI white matter lesion load, which they felt may also lead to more rapid treatment decisions in acute stroke.

Baradaran et al. in AJNR performed a systematic review looking at high-risk features of carotid plaque on CTA, finding that the presence of soft plaque, plaque ulceration and increased carotid wall thickness correlated with ipsilateral ischaemia, whilst plaque calcification had a negative relationship with ischaemia.

Intervention – Two important studies in JNIS this month are again focused on thrombectomy. Frei et al. share their experience of using a standardized thrombectomy protocol (from pre-hospital to IR suite), and show a significant reduction in door to recanalization time. Alondo de Lecinana et al. describe the results of a prospective observational study showing that mechanical thrombectomy is safe and should be performed in patients with contraindication to intravenous thrombolysis.

Tumour – In Neurographics this month, there is a focus on glioma with reference to the 2016 WHO tumour classification (available here). A two-part review by Arevalo et al. in the first part gives an overview of basic tumour genetics covering significant mutations and the updated classification of gliomas, and in the second focuses on imaging features associated with the IDH mutant and wild type (see also the July blog and the review by Smits et al.).

Also with reference to the updated classification, a case series by Nunes et al. in AJNR examines the recently reported entity of a multinodular and vacuolating neuronal tumour, which is a ‘don’t touch’ lesion, and its imaging characteristics.

Inflammatory – Double inversion recovery remains a potentially powerful tool in MS imaging, and Eichinger and colleagues in AJNR have investigated a pre and post contrast and subtraction protocol to compare it to T1 weighted imaging. They demonstrate that DIR is more sensitive in detecting enhancing lesions, and suggest it as an alternative to T1 imaging.

Degenerative – Structural MRI can be of limited use in the setting of motor neuron disease, although volumetric MRI can demonstrate areas of parenchymal loss. Senda and colleagues looked at whether imaging characteristics (volume and DTI) could predict progression in motor neuron disease. They showed that atrophy and particularly grey matter loss, and a decrease in fractional anisotropy, in specific areas beyond just the corticospinal tract correlated with an increased rate of clinical disease progression.

Spine Cardenas et al. provide a useful and comprehensive pictorial review of pathologies of the conus medullaris and cauda equine in Neurographics, covering the spectrum of congenital, infectious/inflammatory, vascular, traumatic and neoplastic aetiologies.

Paediatrics – There is a focus on the rare Menkes disease in AJNR, with a two part review focusing on the vascular/white matter and grey matter changes in this progressive disorder. The authors compare their own case series with the literature for every imaging finding, which makes for a definitive review of this disorder although may be mainly relevant to specialist centres.

More common in everyday practice is the pineal cyst, and Jussila et al. followed up their cohort of pineal cysts in children and showed that the majority do not change, and suggest only re-imaging in the context of unusual radiological features or clinical symptoms.

Although we hope that it will not become necessary in the UK, there is a focused pictorial review in Radiographics this month demonstrating the pre- and postnatal imaging features of Zika virus in the brain covering sonographic and MR findings, and important differential diagnoses.

Miscellaneous – The debate about the use of gadolinium based contrast agents continues, and it is important as radiologists to be informed as to the mechanisms of action being uncovered. A useful review in BJR by the group that initially reported gadolinium deposition in the brain goes through our current knowledge of the mechanisms of gadolinium deposition, and in particular the role of the relatively newly-investigated glymphatic system.

And finally, just in case you wanted another differential for those nonspecific white matter lesions, in Neurology this month Alperin et al. discuss the findings of increased periventricular white matter lesions in returning astronauts. They do not say how often this history was mentioned in the clinical details.

That’s all for now – let us know what you’ve found useful this month!

September Journal Round-Up

Welcome to the September journal round-up (with apologies for the delay). Thank you for the responses to the blogs so far, and please do get in touch with any more ideas for what you would like to see or what you would like to write! Here’s what we’ve been reading this month…

Emergency – Chilvers et al. in Clinical Radiology this month assessed their cohort of trauma cervical spine CT in order to determine the predictors on CT of ligamentous injury on MRI, as well as assessing a normal range of commonly used measurements in this context. They found that in the absence of fractures, the basion-dens interval (>10mm) and widened C0-C1 (>3mm) and C1-C2 (>6mm) facet joints were predictors of significant ligamentous injury at the craniocervical junction, and >50% subluxation of a facet joint and an obscured paraspinal fat pad were predictors in the subaxial spine.

Vascular – The appropriate initial imaging in acute stroke to allow for decisions regarding thrombectomy remains a controversial topic, and in JNIS Ryu et al. have performed a systematic review to assess the utility of perfusion imaging, finding that there is an associated increased probability of a favourable outcome particularly as it may allow inclusion of patients who would otherwise not be considered eligible.

As the treatment of stroke evolves, accurate assessment of CT imaging is paramount. Cora et al. have demonstrated the utility of a validated case archive for training general radiology trainees in the interpretation of CT angiography, showing a reduction in the major discrepancy rate and providing a framework for the case archive which can hopefully be a useful model to extend to other learner groups and topics.

Away from stroke imaging, Silvis et al. provide an excellent clinical overview of venous sinus thrombosis which contains useful context for the radiologist.

Intervention – An important study in Stroke by Achit et al. uses data from the THRACE RCT to demonstrate the cost-effectiveness of mechanical thrombectomy (in combination with intravenous thrombolysis) as opposed to intravenous thrombolysis alone.

In AJNR, Barreras et al. look into a case series of false-negative spinal angiograms, when vascular malformations have subsequently been diagnosed, and highlight important operator factors which led to the misdiagnosis, providing a checklist to avoid similar mistakes in future.

Inflammatory– Multiple sclerosis is on the agenda in AJNR this month, neatly timed ahead of the soon-to-be-unveiled latest update to the McDonald criteria. Two open access articles by McNamara et al. cover the spectrum of multiple sclerosis neuroimaging: the first covers the numerous specific agents used in treatment and the role of MRI, and the second covers pharmacovigilance/safety monitoring and MRI surveillance protocols in more detail.

Infection – Two review articles in Nature Reviews Neurology and Practical Neurology provide an overview of tuberculous meningitis. Wilkinson et al. cover the pathogenesis, clinical features, diagnostic paradigms and management in great detail whilst Shah et al. draw on their experience of patients in East London to provide specific learning points based on five case studies. Taken together they provide useful education on a sadly increasingly common problem.

Degenerative – Normal pressure hydrocephalus can be a difficult diagnosis for the radiologist to make, and Miskin et al. aimed to determine the utility of two techniques, the callosal angle and Evans index. They found that these may act as a useful screening technique to lead to dedicated volumetric imaging.

Paediatric – The risks associated with sedation in children undergoing MRI are not negligible and in Pediatric Radiology, Barkovich et al. examine ways in which the need can be minimise. Protocol rationalisation, motion and noise correction and maximizing the child’s comfort are some possible solutions outlined in this pragmatic article.

Spine Weidauer et al. provide a comprehensive review of imaging of myelopathies, with some excellent diagrams outlining the lesion distribution within the cord for specific aetiologies, and provide a framework for the approach to these tricky clinical scenarios.

That’s all for now, do let us know what you have found helpful this month!

UKNG Annual Meeting Highlights

Dr Juveria Siddiqui attended the UK Neurointerventional Group annual meeting this summer and has kindly recorded some of her highlights from the meeting for us below:

The UK Neurointerventional Group (UKNG) Summer meeting was hosted in Bristol from 9-10th June 2017. It was well-attended by consultant and registrar INRs countrywide, as well as industry representatives. The main focus of the meeting was understandably stroke intervention, with talks covering various aspects of this topic on both days.

The meeting kicked off with a talk on setting up a 24/7 stroke service by UK experts in the field: Dr Andy Clifton (St George’s, London), Professor Phil White (Newcastle), Dr Peter Flynn (Belfast) and Dr Robert Lenthall (Nottingham). Professor White has been closely involved with NHS England’s commissioning of thrombectomy in stroke (announced earlier this year), and discussed American data on mortality citing that smaller units are associated with poorer stroke outcomes.

This suggests that, given the wide range of patient numbers presenting to individual HASUs per year, not every HASU should necessarily provide a stroke thrombectomy service, in order to maintain numbers and encourage skills preservation in units that are service providers. HASUs will likely be expected to demonstrate the numbers performed and their adherence to guidelines in order to continue performing thrombectomy. Following the DAWN trial, which assessed functional outcomes following thrombectomy 6-24 hours following ictus (including wakeup strokes) and terminated early due to high efficacy, the number of stroke patients eligible for thrombectomy is likely to increase.

Following this, talks from Dr Andy Clifton on his experience of implementing a 24/7 stroke thrombectomy service at St George’s Hospital demonstrated that this process required meticulous planning and also discussed the possible hurdles that one may experience. The unit is busy, accepting many patients beyond St George’s catchment area. Dr Clifton discussed the work pattern of the INRs in this unit, based on a 1 in 5-6 rota.

Dr Sanjeev Nayak from Royal Stoke University Hospital followed this with his experience, primarily of stentriever in thrombectomy. His experience of a current 1 in 2 rota covering all neuro-intervention highlighted the need for service expansion and recruitment for the longevity of an INR-led thrombectomy service.

My presentation covered data from the Royal London Hospital’s HASU; a yearlong audit at our unit emphasised that robust initial imaging (CT and CTA) must be a pre-requisite in the quick diagnosis of those eligible for thrombectomy.

Dr Adam Rennie from Great Ormond Street Hospital presented the new RCPCH/Stroke associated Paediatric Stroke guidelines. These guidelines aim to increase awareness of stroke in babies and children, and recommend early unenhanced CT and CTA (neck and intracranial) in any child who is FAST positive but also children with unexplained focal neurological deficit or decreased conscious level. MRI should also be performed if it can be carried out in a timely manner.

The guest speaker, Professor Matthew Gounis, a bioengineering researcher at the University of Massachusetts, USA, provided an intriguing insight into the in-depth laboratory models assessing different clot types and the best modes of retrieval. Use of a balloon guide catheter was associated with improved revascularisation outcomes. There are certain clot types that are easily retrieved, and some that are irretrievable regardless of technique.

There were also a number of excellent talks unrelated to stroke; Dr Wilhelm Kuker’s experience in the pearls and pitfalls of carotid stenting, Dr Andy Clifton’s approach to intracranial vascular lesions in connective tissue disorders and Mr Mario Teo’s neurosurgical management of Moyamoya by vascular anastomosis, following his fellowship at Stanford.

Overall, the meeting was well-organised, interesting and varied, and as well as learning, gave me the opportunity to meet friendly and approachable INRs from all over the UK. There were also useful simulator sessions available. I would recommend the meeting to any budding neuro-interventionalist.

http://ukng.org.uk

Look out for highlights from the BSNR Annual Meeting in the next couple of weeks, and apologies for the delay in the September journal round-up which will be available next week.

Fellowship Experience – Perth, Australia

Dr Lucy Childs is a UK radiology trainee who has been out in Perth, Australia doing her neuroradiology fellowship. She has very kindly shared her experiences and advice on the fellowship with us below:

NIISWA is the Neurological Imaging and Intervention Service of Western Australia.

There is a link here to information about the fellowship: http://niiswa.com/index.php/fellowships.html

There are 3 diagnostic fellows and 1 neuro intervention fellow each year. The fellowship is typically one year long, but can be extended to 2 years, particularly for the interventional fellows.

It’s a tertiary Neuroimaging specialist centre with advanced neuroimaging techniques including CT and MR perfusion, spectroscopy, functional MR imaging etc. NIISWA runs a 24 hour mechanical thrombectomy service for acute strokes, as well as the usual gamut of neurointervention (aneurysms/ AVM management/ stents etc.)

As a fellow you work across two hospital sites: Sir Charles Gairdner Hospital (SCGH) and the Royal Perth Hospital (RPH). These are both public hospitals (like NHS). SCGH is the regional neuro-oncology centre with a large neurosurgical department. The state trauma unit is sited at RPH.

There are two MRI scanners at SCGH one 1.5 and one 3T, (same at RPH). The MRI scanners work almost exclusively performing neuroimaging. The MRI and CT radiographers are excellent, very experienced and tailor scans to the specific clinical requirements, working closely with the neuroradiology team. The MRI scanners work from 0800-1700 for inpatient scanning and 0615-2200 for outpatient scanning with additional out-of-hours oncall service.

The job is busy, there is a large exposure to pathology with a high volume of abnormal scans. Very few ‘normal’ scans are performed by NIISWA. At SCGH CT imaging is reported by general radiologists with referral to NIISWA only when specialist input is required. At this site imaging is predominantly MRI based. All modalities are reported by NIISWA at RPH.

As a diagnostic fellow you are expected to perform fluoroscopically guided lumbar punctures, fluoroscopic and CT guided facet joint injections, fluoroscopically-guided nerve root sleeve injections, fluoroscopically-guided epidural injections and spinal markings prior to surgery. If you are not interested in or not comfortable with performing procedures most days of the week (usually at least 1-2/day) then this fellowship might not be the one for you, as this is entirely expected.

There is the opportunity to do head and neck reporting. H&N reporting is nearly all cross-sectional, with almost no ultrasound imaging as this is performed by sonographers at NIISWA, although you are still part of the FNA service.

As a fellow you actively participate in journal club meetings, CME lectures and MDT presentations. Teaching is generally case based and there is excellent senior consultant supervision at all times.

The pay is excellent. Typically equates to £125,000/ year ($200,000 AUD) when on call payments are included (these are variable). The on call is 1 week in every 4 and you are essentially on call from home 5pm-8am and working your normal hours the rest of the week. Annual leave is unfortunately very low in your first year at only 20 days/year. There are no zero days before or after on calls either.

Western Australia is an enormous geographical area with its own unique challenges. It’s not uncommon for ‘flying doctors’ to bring patients from many hundreds of kilometres away from small remote Australian communities. In combination with socio-economic problems, this leads to cases more often seen in developing countries – indeed it is the only place where I have encountered cases of leprosy.

Overall, this is a very educational fellowship with an excellent supportive neuroimaging team. The downsides would include the lack of time off (to explore the area). Perth also feels like a very ‘new’ city which is currently short on culture and multiculturalism, but is making progressive attempts to improve this. There are also incredible beaches which do go some way in offsetting the lack of art establishments!

Our thanks to Lucy for sharing such detailed information about the fellowship – if you are currently undertaking a neuroradiology fellowship in the UK or abroad, please do get in touch and tell us what you think about it!

August Journal Round-Up

It’s that time of the month again – welcome to the August journal round-up!

Emergency – The longstanding issue of blunt cerebrovascular injury following craniocervical injury was again on the agenda this month; Cook et al. came to the conclusion that for these purposes children may well be little adults, as the modified Denver criteria have a high sensitivity for these injuries. However, the issues of radiation dose and what treatment is appropriate have not yet been settled. To further complicate matters, Grandhi et al. in JNS found that CTA has a high false positive rate for BCVI (in adults), particularly for Biffl grade 1 injuries, and suggest that these should be confirmed with DSA which brings its own problems.

Away from these thorny issues, Rozell et al. present a case based approach to infectious and inflammatory conditions presenting to the emergency department in Emergency Radiology, which may be a particularly useful summary to registrars starting their neuro blocks.

Vascular/Intervention – Optimising endovascular therapy for stroke and the pre-procedural imaging remains a dominant theme of this month’s journal articles. A retrospective analysis of MR CLEAN trial data published in Radiology by Jansen et al. demonstrated that the opacification of cerebral veins (using a scoring system based on three areas) predicted the response to intra-arterial therapy, although this relied on satisfactory venous opacification on a CTA. Sallustio et al. in AJNR showed that using the ASPECTS score on CTA was a better predictor of outcome than using it on non-contrast CT, although also in AJNR Pfaff et al. demonstrated the utility of automated ASPECTS scoring (e-ASPECTS) as this also correlated with outcome (as well as with expert raters).

Tumour – The spectrum of leptomeningeal malignancy and its mimics is covered in a handy pictorial review in Neurographics by Salehi et al., including the multitude of leptomeningeal neoplasms as well as infectious and inflammatory causes. Mimics are also the subject of an article by Starr and Cha in Clinical Radiology, which highlights five key features to alert the radiologist that an apparent meningioma may not be what it seems – significantly high or low T2 hyperintensity, osseous destruction, leptomeningeal extension and lack of a dural tail. Finally, in JNS Starke et al. examine the dreaded pineal cyst, examining key features from their cohort that are associated with hydrocephalus and malignant transformation.

DegenerativeJennings et al. in JAMA Neurology showed the predictive value of dopaminergic imaging in Parkinson’s disease, showing that a combination of hyposmia and positive DAT-SPECT predicts a conversion to PD within four years; this could also be used as a quantitative biomarker to measure disease progression over time. It is worth also checking out the accompanying editorial (by Postuma) which places the findings in context.

Cerebral amyloid angiopathy is a common diagnosis but still presents a diagnostic dilemma and our pathophysiological understanding of the condition remains incomplete. Two articles published this month aim to help tackle this and are complementary in their aims. Firstly, a comprehensive radiological review in Neurographics, by Koren et al., which covers the imaging features and Boston diagnostic criteria as well as the rarer inflammatory subtype. Secondly, a broader, more clinically orientated overview in JNNP by Banerjee et al. examines the current state of knowledge and future directions for diagnosis and treatment.

SpineKralik et al. studied the utility of 3D SPACE imaging for the diagnosis of spinal dural arteriovenous fistula; as expected, abnormal flow voids associated with dAVFs were better seen on 3D imaging, however the authors stress the importance of using this in tandem with 2D T2 imaging for assessing cord signal change.

Miscellaneous – I never know which section PRES belongs in, and it seems I’m in good company as a practical review of the condition outlines in JNNP this month. Gao et al. present a review of the different theories of aetiology for this heterogeneous disorder, and most importantly for the radiologist stress that the diagnosis of PRES is far from the endpoint of investigation and should prompt a search for underlying causes.

With the controversy surrounding the significance of gadolinium deposition in the brain still very much alive, a review of pathology of the dentate nucleus seems timely, and Bond et al. provide a thorough summary of the functional anatomy and conditions affecting this area.

And finally, public service announcement of the month goes to Sriram et al. in JNS, who presented a case of penetrating spinal injury by a swordfish – a key differential to consider in the fisherman presenting with hemiparesis.

That’s all for this month, do let us know what you’ve found useful this month! Coming up over the next couple of weeks we have a summary of the recent UKNG annual meeting, and we’ll have highlights from the BSNR Annual Meeting towards the end of September – do follow us on @BSNRTrainees for updates.

 

BSHNI Annual Meeting – Highlights

The excellent annual BSHNI meeting was held in London at the Royal Society of Medicine last month. Here, BSHNI trainee representative Phil Touska picks his highlights from the meeting:

Highlights from the July 2017 BSHNI meeting:

  • Trauma session
    • Following the tragic events in Manchester and London this year, the first session focused upon the crucial role of radiology in managing such patients.
    • Important messages included:
      • Ensuring all radiology departments plan for emergencies, ensuring that protocols are in place in the case of multiple unexpected simultaneous casualties.
      • With regard to penetrating neck injury, defining the ‘zones’ is less important than defining the structures and viscera transgressed.
      • Facial buttresses are key to assessing and reporting facial skeletal trauma and injuries to the lacrimal fossa may affect important ocular attachments.
      • Radiologists need to be prepared for blast injuries they may be unfamiliar with (see Hare et al. 2007).
    • High Field MR
      • Dr Verbist & Prof Webb presented some of their inspirational work using 7T MR, highlighting some of the advantages, particularly with regard to local staging of head and neck tumours, but technical challenges, such as less predictable tissue heating patterns secondary to the altered electromagnetic field interfaces also arise at high field strength.
    • Robots in the head & neck
      • Transoral robotic surgery (TORS) for oropharyngeal carcinoma is becoming available in several centres across the country – radiology can not only provide staging information for surgical planning, but also highlight surgical risks such as medialised carotid arteries. Loevner et al. provide a useful review of TORS for the head and neck radiologist.
    • Thyroid ablation
      • Drs Morley and Otero highlighted their experiences with radiofrequency ablation of benign thyroid nodules following the recent NICE guidance – early results seem promising (Lim et al. 2013) and it may be a viable alternative to surgery in some cases, but the team highlighted the potential risks (Baek et al. 2012) and the importance of relevant technical skills and facilities.

July Journal Round-Up – Head & Neck

Phil Touska is the new trainee representative for the British Society of Head and Neck Imaging (BSHNI), and here’s his thoughts on the most recent and relevant publications in head and neck radiology:

Head & Neck Cancer

AJCC 8 is on its way and promises to improve the accuracy of staging and correlation with survival and reflects more recent data. The main changes include separate staging for HPV related and non-HPV related SCC, reflecting the more favourable prognosis of HPV related disease. In addition, depth of invasion is now included in the staging of oral cancer (small, but deeply invasive lesions carry a worse prognosis) and there is a new N3b stage for non-HPV related SCC, reflecting extranodal spread (Lydiatt et al. Jan 2017).

Otology

Whilst the ‘third eye’ might provide insight, the ‘third window’ is associated with a diminution of the senses, hearing loss in particular. Although many of us may have come across semicircuar canal dehiscence, the aetiology of the associated hearing loss and the spectrum of similar conditions may be less familiar. Ho et al. provide an excellent insight into the various different abnormalities that may cause ‘third window’ defects (Ho et al.  2017).

Rhinology

A group of rhinologists have recently convened to discuss the scintillating topic of the frontal sinus and its drainage pathway. This resource is helpful if you are communicating with surgeons carrying out endoscopic procedures in this region, alerting them to supra-agger or supra bulla cells (Wormald et al. 2016). A further helpful resource on frontal sinus drainage pathway anatomy can be found in the AJNR (Daniels et al. 2003).

Trauma

Reviewing soft tissue radiographs of the neck for foreign bodies can occasionally result in confusion and pitfalls abound. If you have ever wondered about the location of the triticeous cartilage or wanted to know the ossification patterns of the cricoid and aretyoid cartilages, look no further than Radiographics (Castan Senar et al. 2017), free for RSNA members.

Techniques

There is increasing interest in the use of dual energy CT in the head and neck. It works on the principle of imaging at two tube voltages, the photoelectric effect predominating at the lower voltage; hence, enhancing lesions will attenuate more, increasing conspicuity. The technique can also be used to isolate iodine creating ‘iodine maps’ to delineate lesions, create virtual non-contrast studies and reduce deleterious metal artefact Roele et al. 2017 and Vogl et al. 2012.

Phil can be contacted on bshnitrainees@gmail.com. Look out for his summary of the 2017 British Society for Head and Neck Imaging Annual Meeting coming later this week!

 

  • Lydiatt WM, Patel SG, O’Sullivan B, Brandwein MS, Ridge JA, Migliacci JC, Loomis AM, Shah JP. Head and Neck cancers-major changes in the American Joint Committee on cancer eighth edition cancer staging manual. CA Cancer J Clin. 2017 Mar;67(2):122-137.
  • Ho ML, Moonis G, Halpin CF, Curtin HD. Spectrum of Third Window Abnormalities: Semicircular Canal Dehiscence and Beyond. AJNR Am J Neuroradiol. 2017 Jan;38(1):2-9.
  • Castán Senar A, Dinu LE, Artigas JM, Larrosa R, Navarro Y, Angulo E. Foreign Bodies on Lateral Neck Radiographs in Adults: Imaging Findings and Common Pitfalls. Radiographics. 2017 Jan-Feb;37(1):323-345.
  • Wormald PJ, Hoseman W, Callejas C, Weber RK, Kennedy DW, Citardi MJ, Senior BA, Smith TL, Hwang PH, Orlandi RR, Kaschke O, Siow JK, Szczygielski K, Goessler U, Khan M, Bernal-Sprekelsen M, Kuehnel T, Psaltis A. The International Frontal Sinus Anatomy Classification (IFAC) and Classification of the Extent of Endoscopic Frontal Sinus Surgery (EFSS). Int Forum Allergy Rhinol. 2016 Jul;6(7):677-96.
  • Daniels DL, Mafee MF, Smith MM, Smith TL, Naidich TP, Brown WD, Bolger WE, Mark LP, Ulmer JL, Hacein-Bey L, Strottmann JM. The frontal sinus drainage pathway and related structures. AJNR Am J Neuroradiol. 2003 Sep;24(8):1618-27.
  • Roele ED, Timmer VCML, Vaassen LAA, van Kroonenburgh AMJL, Postma AA. Dual-Energy CT in Head and Neck Imaging. Curr Radiol Rep. 2017;5(5):19.
  • Vogl TJ, Schulz B, Bauer RW, Stöver T, Sader R, Tawfik AM. Dual-energy CT applications in head and neck imaging. AJR Am J Roentgenol. 2012 Nov;199(5 Suppl):S34-9.